We saved patient lives in Phase I, and met or exceed all Phase I milestones. We now propose to verify and extend these results in an expanded trial at 3 leading clinical centers (Stanford, Univ. of California, VA). This Phase II SBIR proposal addresses the need to detect colon ischemia associated with the repair of Abdominal Aortic Aneurysm (AAA), a lethal complication of AAA repair. An abdominal aneurysm is found in 5% of adults over 50, and its repair or rupture is the 13th leading cause of death in the U.S. A lethal complication of AAA repair is colon ischemia (1-2% rate of ischemia to the gut, confirmed in 2004 studies from NYU, SUNY, and DREAM study). Of those developing moderate to severe colon ischemia after AAA repair, the majority die before leaving the hospital of irreversible colon infarction. Early surgical intervention improves outcome ONLY if the ischemia is detected and treated within hours. Once the colon dies and the patient becomes ill, it is too late for repair. Prior to this trial, no reliable early detection technique existed. Moreover, new 2005 studies show that stent repair AFTER rupture of an AAA cuts mortality by half, but results in frequent colon ischemia, suggesting patients with ruptured AAA may benefit from monitoring. In Phase I, we developed and tested a rectal probe to detect acute ischemia, and changed outcome. [unreadable] PHASE I RESULTS: PATIENTS w/ PROBE PATIENTS w/o PROBE [unreadable] Number of Patients in Phase I Study 38 Study Patients 526 Controls [unreadable] ICU Days (patients w/ischemia) 2 Days in ICU 29 Days in ICU [unreadable] (p less than 0.001) [unreadable] Death Rate (patients w/ischemia) 0% Died 55% Died [unreadable] The specific aims of this Phase II (R44) proposal are: (1) to manufacture a commercializable probe to FDA standards, (2) to extend the R43 study into a pivotal NIH-Phase Ill-Type multi-center trial of 500 patients undergoing AAA repair, validating the clinical efficacy of colon monitoring on 5 outcome measures. If successful, the probe will be commercialized. Spectros founders have already founded and taken other biotech firms public (Xenogen), and Spectros itself is selling an SBIR-supported product for anesthesia use. [unreadable] [unreadable] [unreadable]